Method and apparatus for treating filaments



Dec. 4, 1928.

G. E. INMAN METHOD AND APPARATUS FOR TREATING FILAMENTS Filed may 1o, 192e Zd' I f 55035.15* .Ei INA/IAN,

Hrs 1' runway:

Patented i Dec. 4, 1928.

UNITED STATES GEORGE E. INMAN, F EAST CLEVELAND, OHIO, A'SSIGrNOR TO GENERAL ELECTRIYIC PATENT OFFICE.

COMPANY, A CORPORATION OF NEW YORK.

METHOD AND APPARATUS Fon TREATLNG FILAMENTS.

Application led May 10, 1926. Seria1.No 107,883.

. My invention relates to methods and apparatus for applying coatings to very fine wires, and more specifically to methods and apparatus for applying so-called getters to coiled filaments for incandescent lamps and similar devices. Getters are chemicals which' are introduced into incandescent lamps or similar devices for the purpose of improving the performance of the lamp as by improving the vacuum in the case of vacuum devices or' by combining with met-allic vapors and preventing injurious discoloration of the bulb. Heretofore it has been the practice in the caseof coiled filaments to apply the getter by dipping the filaments in a getter solution. The dipping method is slow and messy by comparison with my method, andhas not produced as uniform results. Further features and advantages of my invention will appear from a description of a species thereo v In the drawin Fig. 1 is a perspective of I an apparatus embodying my invention; Fig. 2 is an elevation partia ly in section of the tube for the getter solution; Fig. 3 is an en-- larged plan view of the ilament container; and Fig. 4 is an enlarged view of a coiled filament.

As shown inthe drawing, the filament coil container 10 ordinarily of glass is in the form of a cylinder open at one end and adapted to contain a quantity of filament coils 11. The other end is closed except for the two tubulures 12 and 13. The container l0 is supported in an inclinedfposition, preferably about and is held by a strap 14 on a slide 15 whichengages the parallel-A guides 16 and 17 on a supporting block 18 carried by a base 19. There are two air jets 2O and 21 disposed opposite the open ends ofthe tubulures 12 and 13 respectively. The getter solution is carried in a tube 22 which may be graduated. The lower end of the tube carries a metal end piece 23 which has an outlet nozzle 24. A needle valve 25 preferably of brass projects through said nozzle and at its upper end has a head 26 projecting above the metal upper end piece 26 of the tube. An adjustable cap 27 bears against the said needle holder and the opening of the nozzle 24 may be regulated by means of this cap as the said needle head is provided with an extension 27 surrounded by the spring 27" which serves to'keep the top of the holder aga-inst the said cap 27. The etter solutlonlmay be supplied through tunnel 28 preferably of brass communicated 'with the inlet pipe 29. The rate of flow of the getter solution may be regulated by adjusting needle 25 through the cap 27. The getter tube 1s supported by the brackets 30 and 31 and carried by a standard 32. lhe

air jets 20`and 21 and the air supply pipe connected-thereto are supported by a bracket 33 adjustably mounted on a block 34 which is adjustably supported on an extension from the bracket 31.

The jet 21 and the corresponding tubulure 13 are disposed tangentially of the cylinder 10. The air issuing from the jet 2l serves therefore to whirl the coils rapidly around the bottom of the container. At the same time the air issuing from the jet 20 encounters the getter solution issuing from the nozzle 24 and directs it into the tubulure 'nsk 12 to be sprayed upon'the whirling coils. A

receptacle 35 is provided toreceive any excess of the getter solution which may flow from tubulure 13. The mounting of container 10 is preferably such that tubulure 13 is substantially horizontal and this prevents accumulation of liquid in the container. A ventilator 36 is provided with a suitable exhaust connection to take off the dust and vapors while the apparatus is in operation. The air pressure for the jets 20 and 21 is preferably high. About thirtyfive pounds has been foundv to be suitable.. In adjusting the needle 25, the point should be opposite the center of the tubulure 12.

tering so as to make sure that the proper amount of getter' has been applied. The character of the getter solution and the amount of air pressure are such that the coils do not become wet but are merely moist. If allowed to become Wet, the-coils would stick together and fail to rotate'and vhence would be improperly coated, The getter material, for instance powdered cryolite, is in suspension in a volatile carrier. One solution which has been used was made by adding 200 grams of the powdered getter material to '150 grams of lacquer containing amyl acetate and then diluting by adding four parts of a mixture of 80% methyl alcohol and 20% ether. The presence of the combination of a quick drying carrier such as the alcohol and ether mixture with a relatively slow drier such as the amyl acetate is desirable.

It will be apparent that after a trial the proper adjustments can be made. As a rule the getter flows at the rate of two lor three cubic centimeters per minute while .4 of a cubic centimeter of mixture is usually required for a gram of twenty-live watt coils, and about .7 of a cubic centimeter for a gram of fty watt coils to give the correct ercentage. As the head of getter decreases in the tube, the adjusting cap can be slightly turned to keep the flow constant.

When the predetermined quantity of getter has been applied, the getter `needle is shut down. Then the air is closed off and the coils areremoved and weighed. If the wei ht is too high, the coils are returned to t e gettering vessel and the air is turned on to rotate the coils for a few seconds. This rubs off some of the getter. If the percentage is too low, more getter may be sprayed on without removing the previous coating. Y

What I claim as new and desire to secure by Letters. Patent ofthe United States, is

1. The method of applying getter to fila- `ments for electric incandescent lamps and similar articles which consists in placing a number of said filaments in a receptacle so that they are supported on the bottom thereof, and then spraying the getter material upon said filaments and at the same time directing gas pressure tangentially so as to cause a swirling of said filaments in front of the spray.

2. In an apparatus for applying material to filaments, the combination of a receptacle for holding a number of filaments and having a plurality of openings in its wall near the bottom thereof, a gas pressure jet disposed at each of said openings at least one of which is directed tangentially of the receptale, and means for feeding a liquid contalning said material so as to be en countered by the gas issuing from'at least responding opening.

one of said jets and sprayed into the cor' In Witness whereof, I have hereunto se my hand this 7th day of May, 1926.' i

GEORGE INMAN. 

